Make animation run only once in bge
Let the message set a property to value 1. Then add a property sensor: If property = 1 --> play action.

OR

Let the message set the state with the "State" actuator. In the another state, play the action triggered by an always sensor.

It will never play again ;)

I see you wrote "Vanish". If you want that the object disappears, use the "Invisibility"-Actuator instead of an action actuator and turn "Visible" off.